Corona charges are ions that are generated in the atmosphere surrounding exposed electrical conductors. FIG. 1 illustrates the basic principles of corona charge generation. As known in the art, ions 1 are generated from the conductor 2 that is exposed to the local environment and held at a positive potential relative to the nearby conductor 3 that is at ground potential or floating. A power supply is typically used to apply the appropriate potentials to the conductors. The resulting ions are the driving force for moving molecules, modifying cells, and fusing cells. It is possible to apply a positive or a negative potential to one of the conductors to generate either positive or negative ions. Corona generating elements have been used for many years in devices that are familiar to most people. For example, photocopiers and laser printers use corona generators to impart a charge onto drums/rollers as part of the printing process. In addition, corona generators have been used in the materials handling industry to counter the charges that accumulate in rolled textiles and plastic films. Electrostatic precipitators use corona charge. In addition, the microelectronics industry uses corona charge for various applications.
It is known in the art to manipulate molecules and biological cells through the use of electroporation and electropermeabilization. Electroporation involves the application of a DC electric field to a cell whereby the electric field causes the induction of cell membrane breakdown. When a cell is in an electroporated state it is possible for molecules that do not normally penetrate the cell membrane to gain access to the cytosol. This effect has been exploited in vitro and in vivo for the delivery of drugs, DNA, and other therapeutic agents that have intracellular sites of action. Electroporation requires that physical contact be established between the target cells to be manipulated and the electrodes of the electroporation device. Electroporation techniques that rely on electrode contact cause muscle stimulation and discomfort. The prior art methods are invasive. Invasive treatment translates to increased complications due to infection and sterility, increased complexity of treatment procedures and increased patient discomfort. A need exists in the art for an apparatus and method adapted for the manipulation of molecules and biological cells that reduces patient discomfort and eliminates the inherent complications associated with traditional invasive methods of electroporation. However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.